Recently, Scientific American came out with an article on the history of the evolution of the eye. Intelligent Design proponents have used that as the basis for renewing old creationist arguments against the idea that the eye evolved. See here and here.
The Scientific American article is about the evolution of the physical eye, rather than about the evolution of the visual system. The ID response, too, is about the physical eye. But it is the usual argument about irreducible complexity. According to that argument, a change in the physical eye would have to have a corresponding change in the entire visual processing system, before there could be any benefit. And this is part of why ID proponents and creationists see it as irreducibly complex.